Photographs are often captured under lights with different colors leading to different color casts. For example, in outdoor photographs, illumination from the sun tends to range from white to orange while skylight tends to be blue. Similarly, photographs captured indoors might have a combination of natural lights and incandescent lighting. These combinations of illuminants lead to different color casts in different parts of images. Correcting the color of the lighting in a photograph, a process called white-balancing or color correction, is difficult even when there is only one kind of illumination in the scene. However, it becomes extremely challenging under mixed illumination because each pixel in the image has a different combination of lighting and needs to be handled differently.